There is a phrase I often hear in shops. "I'm not a fan of fermented coffees." And, leaning in from the other side, "Do you have anything fermented?" It is a useful phrase. One word tells you where a person's preference divides. But as a maker, let me restate it precisely, just once. All coffee is fermented.
What people call "fermented" is, broadly, anaerobic coffees, naturals with a strong fermented character, winey coffees and co-ferments. In English they are called funky, winey, boozy. Coffees wearing the complex aromas of fermentation, like wine or kombucha. In short, the phrase is used not as the name of a processing method but as the name of a flavour style.
In the cupping world too, the descriptor "fermented" sits in an interesting place. Too strong, a defect; restrained, an attraction. So fermented flavour is treated not as good or bad but as a matter of intensity. The industry's official vocabulary itself is moving from the era of "fermentation = defect" to "fermentation = style".
This is today's point. Washed coffee, treated as the antonym of fermented, is it unfermented? Of course it is fermented. Openly so. The washed process has a piece of equipment called a "fermentation tank", and in it a fermentation led by lactic acid bacteria takes place (Shen et al., 2023). The "clean acidity" of washed coffee is itself a product of fermentation.
Historically, in the coffee world, the word "fermentation" has been used as the name of the step that breaks down mucilage. So the division "fermented coffee / unfermented coffee" does not hold scientifically. Within the industry there have long been calls for more precise terms.
So what is different? Where the fermentation flavour is placed. It is a difference of design.
Designed in front. Seal, run the fermentation long and deep, and make ester aromas the lead. Anaerobic fermentation and co-fermentation.
Designed in the middle. Dry with the fruit and dissolve the fermentation flavour into the fruit character. Natural and honey.
Designed behind. Fermentation does only the job of making clean acidity and does not appear as a flavour. Washed.
So a person who "doesn't like fermented" does not dislike fermentation. They dislike fermentation flavour put in front. Their cup, too, carries the gift of fermentation as clear acidity.
In front: the anaerobic coffees and the co-ferments (lime, strawberry). Coffees for enjoying the complexity of fermentation. In the middle: natural and honey. Fermentation dissolved in fruit. Behind: washed. Fermentation as the unseen worker.
To anyone who has felt "I don't like fermented", I would first suggest a washed. And if the fruit of a natural starts to feel pleasant, walk little by little toward the front. The road is continuous. All coffees stand on the same ground of fermentation.
Not a formal classification, but a common name for coffees designed with fermentation-derived flavour in the lead, such as anaerobic fermentation and strongly fermented naturals. In English, funky or winey are the nearest expressions.
It is. In the washed "fermentation tank" a fermentation led by lactic acid bacteria takes place, and the clean acidity is its product. The difference is a design that puts fermentation flavour behind rather than in front.
Yes. What you dislike is not fermentation itself but fermentation flavour put in front. A coffee designed with fermentation behind, such as a washed, offers a clear taste.
For the boundary of fermented flavour see Ferment or fruity: where is the line; for the mechanism, The four stages of fermentation; for the design behind, washed; for the design in front, anaerobic fermentation.
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